The headline on this Reuters story reads "Microsoft's Ballmer sells 12 percent stake in company."

In fact, as the story itself explains, Ballmer sold 12 percent *of his stake* in Microsoft. That is, he sold 12 percent of the stock he owns, which, Reuters' story goes on to say, is now, after the stock sale, about 4.2 percent of the company. By comparison, Bill Gates owns about 7.2 percent of Microsoft. No individual could sell 12 percent of the company because no one owns that much of it.